Response modification in NextJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is response modification in Next.js?

Response modification means changing the server's reply before it reaches the user. In Next.js, you can adjust headers, status codes, or body content in server actions or API routes.

beginner

How do you set a custom header in a Next.js API route?

Use the Response object’s setHeader method. For example, res.setHeader('Cache-Control', 'max-age=3600') adds a cache control header.

beginner

Why would you modify the response status code in Next.js?

Changing the status code helps tell the browser or client what happened. For example, res.status(404) means the page was not found, so the client can handle it properly.

intermediate

What is a common use case for modifying the response body in Next.js server actions?

You might add extra data or format the response before sending it. For example, wrapping data in an object with a message or filtering sensitive info.

intermediate

How does Next.js 14+ support response modification in the App Router?

Next.js 14+ uses server actions and the new Response API, letting you create and return custom Response objects with headers, status, and body directly from route handlers.

In Next.js API routes, which method sets a response header?

A res.sendHeader()

B res.getHeader()

C res.setHeader()

D res.modifyHeader()

Use res.setHeader() to add or change headers in the response.

What status code should you use to indicate a resource was not found?

A 200

B 302

C 500

D 404

Status code 404 means 'Not Found', telling the client the resource doesn't exist.

Which Next.js feature allows returning custom Response objects?

A Server Actions

B Client Components

C Static Props

D getServerSideProps

Server Actions in Next.js 14+ let you create and return custom Response objects.

Why modify the response body before sending it?

A To add or format data for the client

B To change the HTTP method

C To speed up the server

D To change the URL

Modifying the body lets you customize the data the client receives.

Which of these is NOT a reason to modify response headers?

A Set content type

B Change the request method

C Control caching

D Add security policies

Response headers cannot change the HTTP request method.

Explain how you would modify a response in a Next.js API route to add a custom header and set a 200 status code.

Think about how to use res.setHeader and res.status in your handler.

Describe the benefits of modifying the response body in Next.js server actions and give an example scenario.

Consider why you might want to change what the client receives.